Great presentation Dave
Thank you very much!
Very good, actual and clear presentation doranchak!
This is really the kind of information I want people to see when they google for the 340.
All questions answered perfectly, well done.
Thanks Jarlve. You and others here did a lot of the work in finding and analyzing the features I talked out in the presentation, and I am very grateful to you!
Thank you very much for uploading the video! The presentation was really good and very informative. I especially liked the nice animations.
Thanks – the animations were fun to work on. It was much easier to show certain ideas instead of trying to explain them in detail.
Great job. You are very well-spoken. All of your experience speaking is showing! I must say, your added humor is a nice touch. 
“…they may be dealing with one or more ersatz Zodiacs–other psychotics eager to get into the act, or perhaps even other murderers eager to lay their crimes at the real Zodiac’s doorstep.“ L.A. Times, 1969
Hey, you mention that diagonal shuffle using 19 characters. (Sorry if I’m not using the right wording). Did you try that with 17?
“…they may be dealing with one or more ersatz Zodiacs–other psychotics eager to get into the act, or perhaps even other murderers eager to lay their crimes at the real Zodiac’s doorstep.“ L.A. Times, 1969
Great job. You are very well-spoken. All of your experience speaking is showing! I must say, your added humor is a nice touch.
Really nice of you to say – thanks!
Hey, you mention that diagonal shuffle using 19 characters. (Sorry if I’m not using the right wording). Did you try that with 17?
Yes, we’ve tried other periods; 17 doesn’t stand out as much as period 19 when it comes to those repeating bigrams. And I think someone’s tried all period values in an automatic solver such as AZdecrypt without any luck.
"17" does have some significance in another area (besides being the width of the cipher grid). It has to do with the length of ciphertext segments that have no repeating symbols in them. So imagine starting at the top left of the cipher and counting how far you get until you hit a symbol you’ve already seen. Write down the length of the segment (excluding the repeating symbol). Then repeat from the 2nd position of the cipher. Then the 3rd. And so on.
Eventually you’ll have a pile of numbers, each representing a length of a segment that has no repeating symbols. You’ll find that in the pile of numbers, there are more 17s than any other number. That’s a pretty interesting feature that Jarlve discovered.
Really interesting presentation…
Thanks for posting it.
CP
No one knows what my disguise consists of…
You’re welcome. I’m glad you found it interesting!
